LEIGH SALES, PRESENTER: The unity of the newly-minted Abbott Government is set to be sorely tested by the potential sale of Australia's largest agriculture business GrainCorp to an American conglomerate.

GrainCorp has a virtual monopoly over the storage, transport and export infrastructure for grain all over Eastern Australia.

Farming groups and the National Party are vehemently opposed to the sale, arguing it's against the national interest to put such vital agricultural assets into foreign hands.

But the Liberal Party's highly disposed towards foreign investment and thinks nixing the sale would send the wrong message. The Treasurer Joe Hockey will have to weigh the political ramifications for the Coalition in which way he decides to go.

Here's Peter McCutcheon.

PETER MCCUTCHEON, REPORTER: Dan Cooper has a lot on his hands. When he's not cutting hay and preparing for next month's grain harvest, he's trying to stop the foreign takeover of Australia's largest agricultural business.

DAN COOPER, GRAIN GROWER: We definitely need foreign investment and agriculture's always had it and probably always will, but we need the right investment. That's the important thing.

PETER MCCUTCHEON: This NSW grain grower is part of a growing rural alliance campaigning to prevent the Australian public company GrainCorp falling into American hands.

DAN COOPER: They're selling off a core piece of infrastructure and especially with the large market share that GrainCorp has, to sell that off to a foreign entity is a big concern for growers.

PETER MCCUTCHEON: At stake is more than $3 billion worth of grain storage and export handling facilities. American agriculture giant Archer Daniels Midlands, or ADM, is pushing hard to buy this critical piece of Australia infrastructure. And for the last few months, grain growers and their political allies, including now Agriculture Minister Barnaby Joyce, have been fighting a rearguard action to stop the sale going ahead.

BARANBY JOYCE, NATIONAL PARTY SENATOR (June): It is definitely against our nation's interests, it's against our farmers' interests and it is against a fair return at the farm gate because nobody has proved otherwise.

BILL HEFFERNAN, LIBERAL PARTY SENATOR: These are serious issues which spell danger for Australia's wheat growers.

PETER MCCUTCHEON: It's the a test of the discipline of the new Abbott Government, pitting free-market advocates against those wanting tougher foreign investment rules in agriculture. And the final decision rests on the shoulders of Treasurer Joe Hockey.

How much pressure is on Joe Hockey at the moment?

DAN COOPER: There's lot of pressure on Joe, absolutely. He'd have the weight of all the East Coast growers on his shoulders at the moment.

PETER MCCUTCHEON: The last big foreign ownership controversy for Australian farmers was the $240 million Chinese takeover of Queensland's Cubbie Station in 2012. This cotton and grain enterprise is the biggest single farm in the country and its sale generated plenty of emotional debate.

DONNA STEWART, BALONNE SHIRE MAYOR (August 2012): I don't want to think that my grandchildren might be feeling the pangs of hunger while food's been taken out of our country and I can see that happening.

PETER MCCUTCHEON: The sale ramped up calls to tighten foreign investment laws, and in opposition, the Coalition pledged to scrutinise more foreign bids and to bringing agricultural experience to the body which assesses overseas applications, the Foreign Investment Review Board.

BILL HEFFERNAN: This is not being xenophobic, this is getting Australians to think about what is the national interest. Do we want to sell our means of production or sell our production? Are we too bloody lazy to do it ourselves?

PETER MCCUTCHEON: But the proposed US takeover of GrainCorp is far more complicated than Cubbie Station, because this is no mere farm up for sale, but the gateway to most of the grains export industry in NSW, Victoria and Queensland.

DAN COOPER: They've essentially got 90 per cent of the ports, they've got 100 per cent of the up-country storage in some places.

PETER MCCUTCHEON: Dan Cooper explains from his property in the central west of NSW that he considers GrainCorp to be, in effect, a monopoly with the power to impose higher fees and charges.

And how far away from your crop here is the silo?

DAN COOPER: Only a couple of k's. We've got a short cart to our local GrainCorp site.

PETER MCCUTCHEON: So it's GrainCorp or nothing?

DAN COOPER: GrainCorp or nothing.

PETER MCCUTCHEON: Nevertheless, the Australian Competition and Consumer Commission, the ACCC, has given the green light to the US takeover of GrainCorp, much to the annoyance of Liberal Senator Bill Heffernan, who's chairing an inquiry into the issue.

BILL HEFFERNAN: And so what the ACCC did in their consideration was to say, "Well this is just one monopoly being taken over by another," but it's not. I mean, there's a hell of a difference and GrainCorp was moving to a position in the market where they woulda had to been reined in anyhow because of their monopoly behaviour.

PETER MCCUTCHEON: But not everyone in the farming community is horrified at the prospect of this agricultural monolith falling into foreign hands.

JOHN SNOOKE, PASTORALISTS AND GRAZIERS ASSOC. OF WA: When we talk about monopoly control, if you want to, I s'pose, say that GrainCorp has monopoly control, we're essentially swapping one owner of that business for another, but the difference is that ADM is willing to bring more money to invest in dysfunctional up-country facilities in NSW and that's something that's been sorely lacking in that grain-growing region.

PETER MCCUTCHEON: John Snooke is the grains chair of the Pastoralists and Graziers Association of WA.

JOHN SNOOKE: If we deter foreign investment, that's the key point here. If the deal is opposed on political grounds, we are sending a signal to agribusiness investors globally that Australia's not open for investment.

PETER MCCUTCHEON: Now, according to the man who negotiated the Cubbie Station deal for his Chinese partner last year, overseas investors are already being scared off by the complexities of dealing with the Foreign Investment Review Board, or FIRB.

TONY MCKENNA, LEMPRIERE CAPITAL: We've spent time talking to the major investors in Asia and they're very aware of the FIRB process and some of them have told us specifically that they've not proceeded with looking at investments because of that.

PETER MCCUTCHEON: So Dan Cooper has a fight on his hands and last week he donned a suit and travelled to Canberra.

As the chair of the Grains Committee of the NSW Farmers Association, Dan Cooper met Treasury officials and the Agriculture Minister, Barnaby Joyce.

The NSW grain farmer emerged cautiously optimistic.

DAN COOPER: Once the Treasury office and everyone else has had a chance to understand our concerns, then there's a pretty good opportunity that, yeah, we may - the sale might not go ahead.

PETER MCCUTCHEON: But the Treasurer's decision may not be a simple yes or no, but one that imposes conditions on ADM's acquisition, and this, according to people who've gone through the process, is the more likely outcome.

TONY MCKENNA: To refuse this application I think would be devastating for the message that it would send to foreign investors. I don't think they've got any choice but to approve it, but they need to negotiate the best conditions they can in the process.

PETER MCCUTCHEON: The details of these conditions could be a deal-breaker. ADM has declined to talk to 7.30, but the company has made it clear it's hoping GrainCorp's substantial footprint in Australia will help it expand into Asian markets. Senator Heffernan says the interest of Australian farmers should be put first.

BILL HEFFERNAN: We don't want countries to come in here with a chequebook, as it were, instead of an army. We want to control our own destiny. To control our own destiny we certainly have to control our revenue base.